As much as we liked the stand and screen-covering functionality Apple's iPad Smart Covers for iPad 2 provided when they launched, the prices and protectiveness were ridiculous -- we feel even stronger about that today than we did before. Regardless, many people purchased them because of their prominence in Apple's retail and online stores, and today, those customers are doubtless looking for ways to protect the uncovered portions of their iPad 2s without throwing away their $40-$70 investments.

Not surprisingly, quite a few manufacturers have released Smart Cover-compatible cases—rear shells that work in conjunction with Apple’s front lid to protect almost the entire tablet without adding significant bulk. We’ve already reviewed Simplism’s Smart Back Cover and SwitchEasy’s CoverBuddy, both of which earned general-level recommendations from us. Today, we’re looking at five new entries into the field: iFrogz’s Backbone ($35), iLuv’s Smart Back Cover ($40, a.k.a. iCC822), Incipio’s Smart Feather ($35), Speck’s SmartShell ($35), and United SGP’s Griff ($50-$53). It’s worth noting up front that these five new rear shells are all more expensive than the first two we reviewed; some cost as much as fully protective iPad cases.

Each of the shells in this category has the same basic structure. They all clip on to the back of the iPad 2, wrapping at least partially around the aluminum rim without covering any of the front bezel. Cutouts along the edges allow for access to the headphone port, mic, Sleep/Wake button, rear camera, side switch and volume rocker, speaker, and Dock Connector port, with some models providing more protection than others. As they are made specifically to be complements to the Smart Cover, the cases have some sort of clearance on their left sides to accommodate the magnetic nubs and spine. Some of the cases have features that set them apart, while others look like clones. Because the combination is so needlessly expensive, we don’t recommend going out and buying both the Smart Cover and one of these shells; rather, we see the shells as a somewhat affordable way to complete your iPad 2’s protection if you already purchased one of Apple’s lids.

iFrogz Backbone is one of the more nondescript offerings. Available in twelve different colors, it provides pretty good body coverage. Unlike some models, this one extends all the way to the top and bottom edges. The cutouts for all of the openings and buttons are done well. They are very close to centered, and offer full access. Instead of just leaving one large opening over the speaker there is a 3 x 3 grid of oval holes that offers a bit more protection without altering the sound in any way. The opening for attaching the Smart Cover is wider than it has to be, leaving about 1/4-inch of the back of the iPad 2 exposed at all times. Overall, it’s a fairly basic option at a higher price than comparably well-designed models.

Almost identical to Backbone, iLuv’s Smart Back Cover has some minor differences but doesn’t justify the higher price. Most of the openings are noticeably tighter, especially the one for the microphone. The plastic of the case runs right up to the edges of the mic, although it doesn’t block it at all. There is no coverage over the speaker, which does leave it at a bit more risk for damage. One noticeable advantage to this model is that the opening for the Smart Cover is narrower, leaving almost no gap between the two accessories. While that is a benefit, Smart Back Cover is the most expensive of the plastic shells and doesn’t offer significantly more protection. It’s not a very good value for the dollar.

Smart Feather from Incipio is an update to the company’s existing Feather line, and is noticeably different than Backbone and Smart Back Cover. The first difference is definitely not great: rather than extending to the top and bottom edges, the case stops a little more than a quarter of an inch away from both, leaving one long opening all the way across, with extra space on the bottom edge for the speaker. This leaves more of the aluminum back exposed without providing any more access or utility. It’s arguable whether the other distinguishing feature is a benefit or a drawback. Instead of just a completely exposed strip for the Smart Cover along the left side, there is a raised ridge that fits over the lid’s magnetic spine. In doing so it offers protection to what would otherwise be exposed metal, and prevents the Smart Cover from being removed. For some this will be an advantage, as they won’t have to worry about the magnets disconnecting accidentally. Others will be turned off by being unable to voluntarily remove the Cover without first removing the shell. A clear plus to this option is that there are eleven different colors. Additionally, like many of Incipio’s cases, Smart Feather includes a screen protector—something none of the other cases on this list come with—as well as a cleaning cloth and a film installation card. These pack-ins make Smart Feather a better value for the dollar than some of its rivals.

If one were to take the design of iLuv’s Smart Back Cover, throw on an additional magnet and lower the price by $5, one would end up with something pretty similar to Speck’s SmartShell. The openings offer a little bit more clearance but are generally pretty similar, including one large hole for the speaker. The opening for the Smart Cover is also similarly sized, with the metal spine and plastic case just about meeting. On the left side of the shell are where there are differences. Along the edge there is a small scoop that provides easier access for lifting the Smart Cover. While pulling the lid up is not a difficult process otherwise, this little design element is still a nice touch. Just a bit to the right of that on the rear of the case, there’s a two-inch-long magnet. This is used to hold the Smart Cover in place when it is folded under, and it works well. Again, it’s not a necessary feature, but it’s certainly a benefit, and shows that Speck didn’t just do the bare minimum in designing this shell, which is otherwise middle-of-pack in pricing. Black satin, orange, pink, and clear models are available.

Of the five options here—and all of the Smart Cover-compatible cases we have seen, for that matter—Griff by United SGP is certainly the most unique; it is also the most expensive. What sets it apart is the material it is made of. Rather than using plastic like all the rest, Griff is a reinforced leather shell. As is usually the case with products from United SGP, the leather is high-quality—better than the thin stuff Apple used on the leather Smart Covers. On the red, black, green, pink, orange, blue, and white versions, it is glossy and textured while the vintage brown is flatter and has less of a shine. Even though the material is different, Griff attaches the same way as the others. It doesn’t extend quite to the top and bottom edges, but is a little bit better than some of the models. At the top, it sits right underneath the microphone, and the opening at the bottom is about the same size. However, instead of leaving the speaker exposed, it is covered with a mesh grating. We really like this idea, and think that it makes a lot of sense for protecting the grill; sound quality is not noticeably impacted. The edge of the headphone port is covered just the slightest bit, but the plugs that we tried fit without any problems. The left edge is rather narrow, meaning that the Smart Cover butts right up against the leather shell.

It’s pretty clear that, with the exception of Griff, most of these shells are almost identical. While some offer a bit more coverage or small extra features, the differences are not huge. For that reason, price becomes an important distinguishing factor when rating the cases. At $25 and with significant protection to top and bottom edges, CoverBuddy received a B+ rating; it is a very good value. For the same price but with more exposed edges, Smart Back Cover from Simplism rated a B. At $10-$15 more each for about the same amount of protection as is offered by CoverBuddy, the shells from iFrogz and iLuv earn a B-. While we like the coverage that they offer, they are by no means worth 40%-60% more. Incipio’s Smart Feather and Speck’s SmartShell both merit a flat B. While we would have preferred if Smart Feather was more protective at the top and bottom edges, the contoured design to accommodate the Smart Cover’s spine as well as the inclusion of a screen protector film bring the value up; SmartShell’s rear magnet and other small design improvements were similarly appreciated. Finally, there’s Griff. The difference in material must be considered in the price. Leather products, particularly high quality ones like this, are naturally more expensive. Griff feels nice to the touch, although it doesn’t cover as much of the iPad 2 as some of the other options, apart from its nice mesh speaker cover. Those who like a purely leather style and are willing to pay more will be happy with it, and as such a B rating is appropriate, though the total cost of Griff plus a leather iPad Smart Cover is crazy at $120. Any of these shells would make good companions to Apple’s Smart Cover, and if you can find a better price than retail on one that didn’t rate quite as high, feel free to bump the rating a little—price is the major reason to pick one of these over the others.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.